For their good appearance, etched metal plates—metal plates whose surface is patterned by etching—have been used as elevator doors or in other applications where a quality appearance is required. Typically, an etched metal plate is manufactured by 1) applying a photosensitive resin onto either or both surfaces of a metal plate to form thereon a resin film; 2) exposing the resin film through a patterned photo mask (also referred to as a “resist pattern”) to cure exposed portions of the photosensitive film; 3) developing away non-exposed portions of the photosensitive resin film; 4) etching the metal with an etchant such as iron(III) chloride solution; and 5) subjecting the cured resin film to alkali treatment.
In the above manufacturing method, the photosensitive resin (also referred to as “etching resist resin”) needs to be in tight contact with the metal plate. For this, pre-treatment is carried out on the metal plate; for example, the metal plate is subjected to such degreasing treatment as alkali degreasing, solvent degreasing or electrolytic degreasing, followed by washing and drying. Moreover, in some cases, acid washing is further carried out after degreasing treatment. Nevertheless, due to the presence of thick oxide coating, metal plates often exhibit poor adhesion to etching resist resin irrespective of adequate degreasing treatment. Insufficient adhesion facilitates intrusion of etchant between the interface of the metal and etching resist resin, which tends to accelerate lateral etching and therefore increases side etching rate. This also facilitates partial separation of the etching resist film, resulting in etching of unwanted portions. Thus it becomes difficult to precisely form an etched metal plate of desired shape unless sufficient adhesion is ensured. Accordingly, etching resist resins need to have sufficient adhesion to metal plates.
Etching resist resins are also required to have sufficient resistance to etchant such as iron(III) chloride solution (etchant resistance), and cured films thereof are required to be readily dissolved and separated by alkali treatment (alkali developability).
To meet these requirements, Patent Documents 1-3 suggest etching resist resin compositions which contain a compound having a carboxylic group and a (meth)acryloyl group in the molecule. In these Documents, resin films obtained by curing of the compositions are said to exhibit high etching resistance and high alkali developability, and the compositions are applied onto metal plates by gravure printing or spay coating.
In the above manufacturing method, a resist pattern is prepared and then an etching resist resin is exposed through the resist pattern. The use of resist pattern enables efficient mass production of etched metal plates, rendering the manufacturing method fit for mass production. However, this method is not suited for the production of various kinds of etched metal plates in small lots.
Thus, for the manufacturing of printed wiring boards where resist etching resin is used as in the case of manufacturing of etched metal plates, methods have been suggested in which inkjet printing is employed for the direct printing of a resist pattern on a metal plate (see Patent Documents 4-7). The manufacturing methods disclosed by these documents realize direct masking of metal plates using CAD image data or other image data without requiring any mask or screen printing plate, thereby eliminating the need to prepare a resist pattern and achieving high workability as well as quickly response to design change. This lends themselves particularly to manufacturing of various kinds of printed wiring boards in small lots. Moreover, the manufacturing methods are believed to offer excellent environmental compatibility, because no development process is needed as direct resist pattern printing is made possible.
Patent Documents 8 and 9 disclose phenoxyethylacrylate-containing inkjet ink compositions, which are disclosed as offering excellent nozzle ejection stability and curability, as well as imparting high processability to cured articles. Patent Document 10 discloses ink compositions which contain a polymerizable compound having phosphoric group, which are said to have high adhesion to recording media.    [Patent Document 1] Japanese Patent Application Laid-Open No. H05-100423    [Patent Document 2] Japanese Patent Application Laid-Open No. H07-76663    [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-129079    [Patent Document 4] Japanese Patent Application Laid-Open No. S56-66089    [Patent Document 5] Japanese Patent Application Laid-Open No. S56-157089    [Patent Document 6] Japanese Patent Application Laid-Open No. S58-50794    [Patent Document 7] Examined Patent Publication No. S59-41320    [Patent Document 8] Japanese Patent Application Laid-Open No. 2002-241647    [Patent Document 9] Japanese Patent Application Laid-Open No. 2007-131755    [Patent Document 10] Japanese Patent Application Laid-Open No. 2006-328227